| /* |
| * van_der_pol_stiff.cpp |
| * |
| * Created on: Dec 12, 2011 |
| * |
| * Copyright 2012 Karsten Ahnert |
| * Copyright 2012-2013 Rajeev Singh |
| * Copyright 2012-2013 Mario Mulansky |
| * |
| * Distributed under the Boost Software License, Version 1.0. |
| * (See accompanying file LICENSE_1_0.txt or |
| * copy at http://www.boost.org/LICENSE_1_0.txt) |
| */ |
| |
| #include <iostream> |
| #include <fstream> |
| #include <utility> |
| |
| #include <boost/numeric/odeint.hpp> |
| |
| #include <boost/phoenix/core.hpp> |
| #include <boost/phoenix/operator.hpp> |
| |
| using namespace std; |
| using namespace boost::numeric::odeint; |
| namespace phoenix = boost::phoenix; |
| |
| const double mu = 1000.0; |
| |
| |
| typedef boost::numeric::ublas::vector< double > vector_type; |
| typedef boost::numeric::ublas::matrix< double > matrix_type; |
| |
| struct vdp_stiff |
| { |
| void operator()( const vector_type &x , vector_type &dxdt , double t ) |
| { |
| dxdt[0] = x[1]; |
| dxdt[1] = -x[0] - mu * x[1] * (x[0]*x[0]-1.0); |
| } |
| }; |
| |
| struct vdp_stiff_jacobi |
| { |
| void operator()( const vector_type &x , matrix_type &J , const double &t , vector_type &dfdt ) |
| { |
| J(0, 0) = 0.0; |
| J(0, 1) = 1.0; |
| J(1, 0) = -1.0 - 2.0*mu * x[0] * x[1]; |
| J(1, 1) = -mu * ( x[0] * x[0] - 1.0); |
| |
| dfdt[0] = 0.0; |
| dfdt[1] = 0.0; |
| } |
| }; |
| |
| |
| int main( int argc , char **argv ) |
| { |
| //[ integrate_stiff_system |
| vector_type x( 2 ); |
| /* initialize random seed: */ |
| srand ( time(NULL) ); |
| |
| // initial conditions |
| for (int i=0; i<2; i++) |
| x[i] = 1.0; //(1.0 * rand()) / RAND_MAX; |
| |
| size_t num_of_steps = integrate_const( make_dense_output< rosenbrock4< double > >( 1.0e-6 , 1.0e-6 ) , |
| make_pair( vdp_stiff() , vdp_stiff_jacobi() ) , |
| x , 0.0 , 1000.0 , 1.0 |
| , cout << phoenix::arg_names::arg2 << " " << phoenix::arg_names::arg1[0] << " " << phoenix::arg_names::arg1[1] << "\n" |
| ); |
| //] |
| clog << num_of_steps << endl; |
| |
| |
| |
| //[ integrate_stiff_system_alternative |
| |
| vector_type x2( 2 ); |
| // initial conditions |
| for (int i=0; i<2; i++) |
| x2[i] = 1.0; //(1.0 * rand()) / RAND_MAX; |
| |
| //size_t num_of_steps2 = integrate_const( make_dense_output< runge_kutta_dopri5< vector_type > >( 1.0e-6 , 1.0e-6 ) , |
| // vdp_stiff() , x2 , 0.0 , 1000.0 , 1.0 |
| // , cout << phoenix::arg_names::arg2 << " " << phoenix::arg_names::arg1[0] << " " << phoenix::arg_names::arg1[1] << "\n" |
| // ); |
| //] |
| //clog << num_of_steps2 << endl; |
| |
| |
| return 0; |
| } |